Why Carrier Screening for Cystic Fibrosis is Important...
Carrier screening tests help identify individuals who may have an increased risk of having a baby with certain genetic conditions. Even if you are healthy, have no family history of the condition, or even already have healthy children, you may be a carrier of a genetic condition. One of these conditions is CYSTIC FIBROSIS.
What is Cystic Fibrosis?
Cystic Fibrosis (CF) is one of the most common genetic conditions in the United States. It is caused by changes in the CFTR gene. Changes in this gene cause the body to produce thick mucus that can affect breathing, digestion and other organs. CF does not affect everyone the same way, some people may be more severely affected than others. Symptoms range from moderate to severe–not everyone with CF is affected in the same way.
Approximately 1 in 30 Americans–more than 10 million people–are carriers of CF. While the risk of being a CF carrier is dependent upon one’s ethnicity and family history, individuals of all racial and ethnic groups may be carriers of CF.
How is Cystic Fibrosis Inherited?
To be affected with CF, an individual must inherit two disease-causing mutations–one from each parent, each of whom is a ‘carrier’ of a CF gene mutation. Carriers have only one disease-causing mutation and most often have no symptoms of CF. However, when an individual has two disease-causing mutations, it results in the individual having CF. If both parents are CF carriers, there is a 1 in 4 (25%) chance that a child will have CF. If only one parent is a CF carrier, there is no chance that a child will have CF; however, there is a 1 in 2 (50%) chance that a child will be a CF carrier.
Who Should Consider Cystic Fibrosis Carrier Screening?
The American College of Obstetricians and Gynecologists (ACOG) and the American College of Medical Genetics (ACMG) recommend cystic fibrosis carrier screening be offered to all Caucasian couples (including Ashkenazi Jews) who are pregnant or considering pregnancy, and also made available to all patients regardless of ethnicity.
Indications for CF carrier screening include:
- Members of couples who are pregnant or planning a pregnancy
- Individuals with a family history of CF
- Individuals with negative results from smaller mutation panels when individual has family history of CF
- Individuals who have a reproductive partner who is a CF carrier.
The CF carrier screening test is a simple blood test and results are typically available to your doctor within one week.
What Does a Positive CF Carrier Screen Test Result Mean?
A positive CF carrier screening test result means you have one copy of a mutation that is known to cause CF. It does not mean you have CF. If you are found to be a CF carrier, then your partner should be tested. If you are both found to be CF carriers, your doctor, genetic counselor or other healthcare provider will discuss reproductive and prenatal testing options with you.
What Does a Negative CF Carrier Screen Test Result Mean?
A negative CF carrier screening test significantly reduces your risk to be a CF carrier, but it does not reduce your risk to zero. Because this test does not screen for all CF mutations, and because not all CF mutations may even be known at this time, your risk to be a CF carrier is reduced, but is not zero.